Apparatus used for packaging bacon, cold cuts, and other types of sliced food products into output packaged units typically convey the sliced food products from an upstream food processing station, such as a slicer, cooking oven, and the like, to an interleaving station where a carrier sheet is positioned to receive the sliced food products in overlapping or shingled arrangement thereon. When a predetermined number of sliced food products have been arranged on the carrier sheet, the output unit is transferred to a downstream wrapping or stacking station for output packaging.
Prior interleaving apparatus have generally used controls to deposit the sliced food products on a conveyor in groups separated by gaps or to halt the conveying of food products as each group of food products is conveyed to a receiving station to be deposited on a carrier tray or other transport member. For example, in U.S. Pat. No. 4,532,751 to Mally et al., the food products are deposited on a supply conveyor separated by gaps between groups, and when a detector detects a gap in the food products, an interleaver control cuts the trailing edge for a current carrier sheet and advances it from the receiving station while advancing the leading edge for the next carrier sheet to the receiving station. The conventional equipment has limitations in that it cannot accept food products that are randomly or continuously arranged on the conveyor, nor can it properly handle food products where the spacing between products or the gap between groups of food products are not precisely maintained.
Other food packaging systems, such as shown in U.S. Pat. No. 4,690,269 to Takao, and U.S. Pat. No. 4,852,717 to Ross et al., have controlled the speed of a downstream receiving conveyor for receiving a number or group of food articles in response to detection of the food articles on an upstream supply conveyor so that the articles can be accurately transferred in groups in a desired spaced relation even though the articles may not be a constant distance apart on the food supply conveyor. U.S. Pat. No. 3,870,139 to Wagner teaches the concept of operating the receiving conveyor at a lower speed than the supply conveyor to receive food articles in a shingled arrangement thereon, then operating it at a higher speed to advance a deposited shingled group to an output. However, the prior systems have not satisfactorily provided for the automatic interleaving of carrier sheets cut from a roll to receive food products supplied randomly or continuously on a supply conveyor, nor for automatic stacking of a number of output units of sheet-carried sliced food products for final packaging.
In my copending prior U.S. patent application referred to above, an apparatus and method for interleaving a carrier sheet with food product units thereon has a supply conveyor for continuously conveying food product units with random spacings therebetween, a delivery section for continuously delivering units from the supply conveyor to a drop-off point, a source for supplying carrier sheets to receive units thereon, a detector for detecting the passage of the units past a predetermined position from the drop-off point, an indexing conveyor for moving each carrier sheet to receive the units at the drop-off point in timed relation to their arrival there, a counter for counting down the arrival of each detected unit to the drop-off point, and a programmable controller for controlling the indexing conveyor to advance the carrier sheet incremental amounts at the drop-off point for receiving each unit in timed relation to their detection, count-down, and arrival at the drop-off point.